
#ifndef __ui_base_menu_model_h__
#define __ui_base_menu_model_h__

#pragma once

#include <windows.h>

#include "base/string16.h"

#include "menu_model_delegate.h"

class SkBitmap;

namespace gfx
{
    class Font;
}

namespace ui
{

    class Accelerator;
    class ButtonMenuItemModel;

    // An interface implemented by an object that provides the content of a menu.
    class MenuModel
    {
    public:
        // The type of item.
        enum ItemType
        {
            TYPE_COMMAND,
            TYPE_CHECK,
            TYPE_RADIO,
            TYPE_SEPARATOR,
            TYPE_SUBMENU
        };

        virtual ~MenuModel() {}

        // Returns true if any of the items within the model have icons. Not all
        // platforms support icons in menus natively and so this is a hint for
        // triggering a custom rendering mode.
        virtual bool HasIcons() const = 0;

        // Returns the index of the first item. This is 0 for most menus except the
        // system menu on Windows. |native_menu| is the menu to locate the start index
        // within. It is guaranteed to be reset to a clean default state.
        // IMPORTANT: If the model implementation returns something _other_ than 0
        //            here, it must offset the values for |index| it passes to the
        //            methods below by this number - this is NOT done automatically!
        virtual int GetFirstItemIndex(HMENU native_menu) const;

        // Returns the number of items in the menu.
        virtual int GetItemCount() const = 0;

        // Returns the type of item at the specified index.
        virtual ItemType GetTypeAt(int index) const = 0;

        // Returns the command id of the item at the specified index.
        virtual int GetCommandIdAt(int index) const = 0;

        // Returns the label of the item at the specified index.
        virtual string16 GetLabelAt(int index) const = 0;

        // Returns true if the menu item (label/icon) at the specified index can
        // change over the course of the menu's lifetime. If this function returns
        // true, the label and icon of the menu item will be updated each time the
        // menu is shown.
        virtual bool IsItemDynamicAt(int index) const = 0;

        // Returns the font use for the label at the specified index.
        // If NULL, then use default font.
        virtual const gfx::Font* GetLabelFontAt(int index) const;

        // Gets the acclerator information for the specified index, returning true if
        // there is a shortcut accelerator for the item, false otherwise.
        virtual bool GetAcceleratorAt(int index,
            Accelerator* accelerator) const = 0;

        // Returns the checked state of the item at the specified index.
        virtual bool IsItemCheckedAt(int index) const = 0;

        // Returns the id of the group of radio items that the item at the specified
        // index belongs to.
        virtual int GetGroupIdAt(int index) const = 0;

        // Gets the icon for the item at the specified index, returning true if there
        // is an icon, false otherwise.
        virtual bool GetIconAt(int index, SkBitmap* icon) const = 0;

        // Returns the model for a menu item with a line of buttons at |index|.
        virtual ButtonMenuItemModel* GetButtonMenuItemAt(int index) const = 0;

        // Returns the enabled state of the item at the specified index.
        virtual bool IsEnabledAt(int index) const = 0;

        // Returns true if the menu item is visible.
        virtual bool IsVisibleAt(int index) const;

        // Returns the model for the submenu at the specified index.
        virtual MenuModel* GetSubmenuModelAt(int index) const = 0;

        // Called when the highlighted menu item changes to the item at the specified
        // index.
        virtual void HighlightChangedTo(int index) = 0;

        // Called when the item at the specified index has been activated.
        virtual void ActivatedAt(int index) = 0;

        // Called when the item has been activated with given event flags.
        // (for the case where the activation involves a navigation).
        // |event_flags| is a bit mask of ui::EventFlags.
        virtual void ActivatedAt(int index, int event_flags);

        // Called when the menu is about to be shown.
        virtual void MenuWillShow() {}

        // Called when the menu has been closed.
        virtual void MenuClosed() {}

        // Set the MenuModelDelegate. Owned by the caller of this function.
        virtual void SetMenuModelDelegate(MenuModelDelegate* delegate) = 0;

        // Retrieves the model and index that contains a specific command id. Returns
        // true if an item with the specified command id is found. |model| is inout,
        // and specifies the model to start searching from.
        static bool GetModelAndIndexForCommandId(int command_id, MenuModel** model,
            int* index);
    };

} //namespace ui

#endif //__ui_base_menu_model_h__